diff --git a/src/header.h b/src/header.h
index 919afdf..dbadd9c 100644
--- a/src/header.h
+++ b/src/header.h
@@ -39,8 +39,8 @@
 #define FIELD_BITS_2003     512
 #define FIELD_BYTES_2003    64
 
-#define NEXTNBITS(field, n, offset)    (((QWORD)field >> offset) & ((1ULL << (n)) - 1))
-#define FIRSTNBITS(field, n)           NEXTNBITS(field, n, 0)
+#define NEXTSNBITS(field, n, offset)    (((QWORD)field >> offset) & ((1ULL << (n)) - 1))
+#define FIRSTNBITS(field, n)           NEXTSNBITS(field, n, 0)
 
 // Confirmation ID generator constants
 #define SUCCESS 0
@@ -52,6 +52,7 @@
 #define ERR_UNLUCKY 6
 
 // Type definitions
+typedef bool     BOOL;
 typedef uint8_t  BYTE;
 typedef uint16_t WORD;
 typedef uint32_t DWORD;
@@ -95,8 +96,21 @@ Options parseCommandLine(int argc, char* argv[]);
 void showHelp(char *argv[]);
 
 // xp.cpp
-bool verifyXPKey(EC_GROUP *eCurve, EC_POINT *generator, EC_POINT *publicKey, char (&cdKey)[25]);
-void generateXPKey(EC_GROUP *eCurve, EC_POINT *generator, BIGNUM *order, BIGNUM *privateKey, DWORD pRaw, char (&cdKey)[25]);
+bool verifyXPKey(
+        EC_GROUP *eCurve,
+        EC_POINT *generator,
+        EC_POINT *publicKey,
+        char (&cdKey)[25]
+);
+
+void generateXPKey(
+        EC_GROUP *eCurve,
+        EC_POINT *generator,
+        BIGNUM *order,
+        BIGNUM *privateKey,
+        DWORD pRaw,
+        char (&cdKey)[25]
+);
 
 // server.cpp
 
diff --git a/src/xp.cpp b/src/xp.cpp
index 28f9ec5..ef1e9ab 100644
--- a/src/xp.cpp
+++ b/src/xp.cpp
@@ -18,27 +18,39 @@
 #include "header.h"
 
 /* Unpacks the Windows XP Product Key. */
-void unpackXP(QWORD (&pRaw)[2], DWORD &pSerial, DWORD &pHash, QWORD &pSignature) {
-
+void unpackXP(
+        QWORD (&pRaw)[2],
+        DWORD &pSerial,
+        DWORD &pHash,
+        QWORD &pSignature
+) {
     // We're assuming that the quantity of information within the product key is at most 114 bits.
     // log2(24^25) = 114.
 
     // Serial = Bits [0..30] -> 31 bits
     pSerial = FIRSTNBITS(pRaw[0], 31);
 
-    // Hash (e) = Bits [31..58] -> 28 bits
-    pHash = NEXTNBITS(pRaw[0], 28, 31);
+    // Hash = Bits [31..58] -> 28 bits
+    pHash = NEXTSNBITS(pRaw[0], 28, 31);
 
-    // Signature (s) = Bits [59..113] -> 55 bits
-    pSignature = FIRSTNBITS(pRaw[1], 51) << 5 | NEXTNBITS(pRaw[0], 5, 59);
+    // Signature = Bits [59..113] -> 56 bits
+    pSignature = FIRSTNBITS(pRaw[1], 51) << 5 | NEXTSNBITS(pRaw[0], 5, 59);
 }
 
 /* Packs the Windows XP Product Key. */
-void packXP(QWORD (&pRaw)[2], DWORD pSerial, DWORD pHash, QWORD pSignature) {
-    pRaw[0] = FIRSTNBITS(pSignature, 5) << 59 | FIRSTNBITS(pHash, 28) << 31 | pSerial;
+void packXP(
+        QWORD (&pRaw)[2],
+        DWORD pSerial,
+        DWORD pHash,
+        QWORD pSignature
+) {
+    // The quantity of information the key provides is 114 bits.
+    // We're storing it in 2 64-bit quad-words with 14 trailing bits.
+    // 64 * 2 = 128
 
-    // sig is 56 bits long, 5 of them are used -> 51 bits remaining
-    pRaw[1] = NEXTNBITS(pSignature, 51, 5);
+    // Signature [114..59] <- Hash [58..31] <- Serial [30..1] <- Upgrade [0]
+    pRaw[0] = FIRSTNBITS(pSignature, 5) << 59 | FIRSTNBITS(pHash, 28) << 31 | pSerial;
+    pRaw[1] = NEXTSNBITS(pSignature, 51, 5);
 }
 
 /* Verify Product Key */